>>536265569
I don't remember if there's an exact reason that sparked it beyond this (someone else can chime in if they're more informed), but she's been musically inclined since she was young and ended up striving to have that "perfect performance" so she pushes herself to reach that goal. Once she went off to Tokyo on her own she got into idols and it just evolved from there. The pursuit of perfection meshed well enough with becoming a top idol.